ABB POWER T&D COMPANY, INC. — 00:90:4F (MA-L)

The OUI prefix 00:90:4F is registered to "ABB POWER T&D COMPANY, INC." at 7036 Snowdrift Road, Allentown, PA 18106, US — an MA-L (24-bit, large) block covering the range 00:90:4F:00:00:00 through 00:90:4F:FF:FF:FF. ABB Power T&D was a North American subsidiary of the ABB Group (the Swiss-Swedish multinational headquartered in Zurich), building power transmission and distribution equipment: protective relays, intelligent electronic devices (IEDs), substation automation systems, and distribution-automation hardware. The Allentown facility historically housed a Relay Division making protective relays and definite-time-delay timing devices; a separate Bloomington, Indiana plant (the former Westinghouse site) ran the Protective Equipment and Distribution Automation Equipment divisions until its closure and demolition in 2006. The practical significance of this OUI is its operational-technology (OT) / ICS context: a network interface presenting 00:90:4F is almost certainly grid-protection or substation-automation hardware — a relay, IED, or automation gateway — built for electric-utility transmission and distribution and critical-infrastructure environments. These devices speak substation protocols (IEC 61850, GOOSE, DNP3, Modbus TCP) and are intended to live behind firewalls on segmented OT networks, never directly internet-exposed. ABB is a well-documented ICS vendor with an active CVE history and multiple CISA ICS advisories across its product lines, so a 00:90:4F device surfacing on a flat corporate IT network is an anomaly worth an OT-segmentation review. Note that this Allentown entity is distinct from ABB T&D Spa (the Italian subsidiary in Dalmine, Bergamo) and from the generic ABB Group MAC blocks. As with all MAC OUIs, IEEE publishes no registration date for this assignment; any "date registered" on third-party lookup tools is a database artifact, not an IEEE fact.

IEEE assignment

00:90:4F → ABB POWER T&D COMPANY, INC. [Confirmed] — IEEE MA-L (OUI 00904F), corroborated by uic.io

Registry / block size

MA-L (24-bit OUI), range 00:90:4F:00:00:00 – 00:90:4F:FF:FF:FF [Confirmed] — IEEE MA-L / uic.io. NOTE: IEEE's public OUI data publishes NO assignment/registration date (the IEEE MA-L registry columns are only Registry, Assignment, Organization Name, Organization Address); any "date registered" on third-party tools is a database artifact, not an IEEE fact.

Registered address / country

7036 Snowdrift Road, Allentown, PA 18106, US [Confirmed] — IEEE MA-L; uic.io

Company status

ABB Power T&D was a subsidiary of the ABB Group (Zurich); the Allentown site later operated under the "ABB Automation" name [Confirmed] — bloomingpedia.org, business listings

Industry

electric power transmission & distribution equipment / substation automation (OT/ICS) [Confirmed] — d&b business directory; tdworld.com

Device types

protective relays / numerical IEDs, substation-automation IEDs, distribution-automation equipment, teleprotection interfaces, and SCADA/control components for power T&D networks [Likely] — abb.com (Relion 615/REF615 series, REC670 IED), docplayer.net (Relay Division timing devices). Tagged Likely because the device-to-OUI mapping is inferred from ABB's product line, not from a per-device OUI manifest.

Communication protocols

IEC 61850 (incl. GOOSE), DNP3, Modbus TCP over Ethernet for substation networking [Likely] — abb.com REF615 IEC 61850 guideform spec

Security context

OT/ICS asset class — devices belong in segmented substation/grid networks behind firewalls, never internet-exposed; ABB has an active ICS CVE history and multiple CISA ICS advisories across product lines; a 00:90:4F device on a flat IT network warrants OT-segmentation review

[Confirmed] — cisa.gov ICS advisories, abb.com cybersecurity guidance

Related entities

ABB Group (parent, Zurich); ABB T&D Spa / SACE T.M.S. (Italian subsidiary, Dalmine Bergamo — separate OUI block); broader ABB Ltd group MAC blocks. The Allentown entity is distinct from each. [Confirmed] — hwaddress.com, maclookup.app

Historic note

the Bloomington, IN facility (Protective Equipment + Distribution Automation divisions, former Westinghouse site) closed and was demolished in 2006 [Confirmed] — bloomingpedia.org

Registration date

Unknown — IEEE publishes no OUI registration dates; no first-party date source found [Unknown] — (no citation; honest null)

IANA reference

blank (this is a MAC OUI entry, not an IANA protocol registration) [Confirmed] — N/A

Analyst note

00:90:4F reliably flags ABB power-T&D OT hardware for asset classification; its appearance outside an OT/substation segment is the signal worth investigating, not the device's mere identity.